Image: Wikipedia - Alvesgaspar
According to a warning that is spreading rapidly via Facebook and other social media outlets, UK residents should watch out for the False Widow spider. The message warns that bites from the spider can lead to amputations.
Adult spiders are capable of biting humans. Spiders are not aggressive and most injuries to humans are defensive bites delivered when a spider becomes unintentionally squeezed or pinched.
The bite of the false widow spider can be medically significant in humans, but usually without any long-lasting effects.
Reports from those bitten describe a certain amount of pain, which often radiates along the limb or part of the body where bitten, and often a degree of swelling in the affected part. Some describe fever and a general feeling of being unwell. These symptoms may last for a couple of days but the total effect is unlikely to be more serious than that.
There have been sensationalized media reports about significant injuries supposedly caused by bites from the spider. A 2012 Daily Mail article describes a case in which a woman was told by doctors that her hand might need to be amputated after she was allegedly bitten by one of the spiders. In another 2012 case reported by The Sun, a man in Yorkshire was told that he might lose his arm after he was allegedly bitten by a False Widow while gardening. However, in neither case was a False Widow actually proven to be the cause of the injuries. And, both victims later recovered without the need for amputations.
In another case, a young father collapsed and was taken to hospital after he was bitten multiple times by a False Widow that was in his clothing. The man also recovered without long term effects.
But, as noted, in most cases bites from the spider are comparatively minor. Of course, just as some people may have adverse and non-typical reactions to bites from bees or other insects, some victims of False Widow bites may experience more serious reactions. The Natural History museum article further notes:
More serious symptoms have occasionally been reported, but are likely to be the exceptional reaction of individuals to the venom. It is always advisable to seek medical attention if symptoms persist.
The warning suggests that bites can lead to amputations. However, there are no credible reports about victims having limbs amputated as a result of False Widow bites. And there have been no reported deaths from the spiders.
The warning states that the "spider is reported to be now in the UK", thus, implying that the False Widow has only recently arrived there. However, the spider has been in the UK for well over a century, having probably arrived via shipments of bananas from the Canary Islands. It is thought to be continually reintroduced to various ports via banana imports. The species has strongholds on the Dorset and Hampshire coast. That said, there are indications that the species is now spreading to other areas of the UK.
An article about the warning on ThatsNonsense.com points out that the image used in the warning was taken by Ian A. Kirk and published on his flickr account in 2010. Ian found the spider in his conservatory and placed it in a bowl to be photographed. It is unclear who created the above warning and reused Ian's photograph.
The bottom line? People, not only in the UK, but everywhere, should certainly be cautious of spiders, especially if they do not recognize the species. And, if you suffer an adverse reaction from a spider's bite, you should of course seek medical help as soon as possible.
Last updated: May 3, 2013
Steatoda nobilis (false widow spider)
'I nearly lost my hand to Britain's most poisonous spider'
Spider bite almost cost me an ARM
False Widow Spider in the UK - Facebook Rumour
Steatoda nobilis ( False Widow Spider)